1. Field of the Invention
The present invention relates to an image processing device and a method for operating an endoscope system, for performing diagnoses based on observation of a ductal structure and capillary vessels.
2. Description Related to the Prior Art
Diagnoses using endoscope systems are widely performed in current medical care. The endoscope system includes a light source device, an electronic endoscope, and a processor device. Observation of an inside of an observation object is performed using the endoscope system. Such observation includes screening observation and magnified observation. In the screening observation, a potential lesion, which is a site with a high possibility of being a lesion, such as a brownish area or redness is detected from a far view. The magnified observation is performed in the case where such a potential lesion is detected. In the magnified observation, a zooming lens is used to magnify the potential lesion so as to perform careful examination of the potential lesion. As the magnified observation, in recent years, “VS classification” in which diagnoses based on observation of a fine membrane structure are performed, has been conducted.
In the “VS classification”, diagnoses based on observation of capillary vessels in a surface layer of a mucous membrane and diagnoses based on observation of a microstructure of the surface layer of the mucous membrane are separately performed. Therefore, it is required to enhance the display of both of the capillary vessels and the microstructure. For the display enhancement, for example, it is possible to extract blood vessel portions from a predetermined image and enhance only the display of the extracted blood vessel portions, as disclosed in United States Patent Application Publication No. 2012/0197076 corresponding to Japanese Patent Laid-Open Publication No. 2012-152459. According to United States Patent Application Publication No. 2012/0197076, since the display of the blood vessel portions is enhanced while the microstructure other than the blood vessel portions remains to be displayed without being disappeared, observation of both of the capillary vessels and the microstructure becomes facilitated. Further, since each of the capillary vessels and the microstructure has mid-frequency components and high-frequency components, it is possible to enhance the display of both of the capillary vessels and the microstructure by performing high-pass filtering as disclosed in United States Patent Application Publication No. 2008/0306338 corresponding to Japanese Patent No. 5057675.
In the recent “VS classification”, it has become clear that the existence of the blood vessels hinders accurate diagnoses of the microstructure in performing diagnoses based on observation of the microstructure. For example, in the case where blood vessels are contained in part of the microstructure which has been already disappeared, an area surrounded by the blood vessels may look like the microstructure. In such a case, possibility of misdiagnosis is increased. Consequently, it is required to generate and display an endoscope image, in which one of the capillary vessels and the microstructure does not impair the visual recognition of the other of them, by performing display control. In the display control, the display of one of the capillary vessels and the microstructure is enhanced and the display of the other of them is suppressed (i.e., selective enhancement/suppression of the display of the capillary vessels and the microstructure is performed), such that the visual recognition of the capillary vessels and the visual recognition of the microstructure are different from each other.
Although United States Patent Application Publication No. 2012/0197076 discloses selective enhancement/suppression of the display of the superficial blood vessels and the deep blood vessels, United States Patent Application Publication No. 2012/0197076 does not disclose selective enhancement/suppression of the display of the capillary vessels and the microstructure. Further, although United States Patent Application Publication No. 2008/0306338 discloses a filtering process capable of enhancing the display of both of the microstructure and the capillary vessels, it is impossible to perform selective enhancement/suppression of the display of the capillary vessels and the microstructure by the filtering process disclosed in United States Patent Application Publication No. 2008/0306338.